Linux Kernel Hackers' Guide

Due to the fact that nearly every post to this site recently has been
either by rude cracker-wannabes asking how to break into other people's
systems or a request for basic technical support, posting to the KHG
has been disabled, probably permanently. For now, you can read old
posts, but you cannot send replies. In any case, there are now far
better resources available.

Alessandro Rubini wrote Linux Device Drivers, which is what the KHG could have been
(maybe) but isn't. If you have a question and can't find the answer
here, go get a copy
of Linux Device
Drivers and read it--chances are that when you are done, you
will not need to ask a question here.

Table of Contents

The most common Linux kernel programming task is writing
a new device driver. The great majority of the code in the
kernel is new device drivers; between 1.2.13 and 2.0 the
size of the source code more than doubled, and most of
that was from adding device drivers.

The KHG is just one collection of information about the
Linux kernel. There are others!

Membership and Subscription

At the bottom of the page, you will notice two hyperlinks
(among several others): Subscribe and Members.
Using the KHG to its fullest involves these two hyperlinks, even
though you are not required to be a member to read these pages and post
responses.

Membership

HyperNews membership is site-wide. That is, you only need to
sign up and become a member once for the entire KHG. It doesn't
take much to be a member. Each member is identified by a unique
name, which can either be a nickname or an email address. We
suggest using your email address; that way it will be unique and
easy to remember. On the other hand, you may want to choose a
nickname if you expect to be changing your email address at any
time.

We also want your real name, email address,
and home page (if you have one). You can give us your phone and
address if you want. You will be asked to choose a password.
You can change any of these items at any time by clicking on
the Membership hyperlink again.

Subscription

Subscribing to a page
puts you on a mailing list to be sent notification of any new
responses to the page to which you are subscribed. You
subscribe separately to each page in which you are interested
by clicking the Subscription link on the page to which
you want to subscribe. You are also subscribed, by default, to
pages that you write.

When you subscribe to a page, you subscribe to that page
and all of its responses.

Contributing

Please respond to these pages if you have something to add.
Think of posting a response rather like posting to an email list,
except that an editor might occasionally come along to clean
things up and/or put them in the main documents' bodies. So if you
would post it to an email list in a similar discussion, it is
probably appropriate to post here.

In order to make reading these pages a pleasure for everyone, any
incomprehensible, unrelated, outdated, abusive, or other completely
unnecessary post may be removed by an administrator. So if you have
a message that would be inappropriate on a mailing list, it's probably
also inappropriate here.

The administrators have the final say on what's appropriate.
We don't expect this to become an issue...

About the new KHG

The Linux Kernel Hackers' Guide has changed quite a
bit since its original conception four years ago. I struggled
along with the help of many other hackers to produce a document
that lived primarily on paper, and was intended to document the
kernel in much the same way that a program's user guide is
intended to document the program for users.

It was less successful than most user guides, for a number
of reasons:

I was working on it part time, and was otherwise busy.

The Linux kernel is a moving target.

I am not personally capable of documenting the entire
Linux kernel.

I became far too concerned with making the typesetting
pretty, getting bogged down in details and making the
document typographically noisy at the same time.

I floundered around, trying to be helpful, and made at least
one right decision: most of the people who needed to read the
old KHG needed to write device drivers, and the most
fully-developed part of the KHG was the device driver section.

There is a clear need for further development of the KHG,
and it's clear that my making it a monolithic document stood in
the way of progress. The KHG is now a series of more or less
independent web pages, with places for readers to leave
comments and corrections that can be incorporated in the
document at the maintainer's leisure--and are available to
readers before they are incorporated.

The KHG is now completely web-based. There will be no
official paper version. You need kernel source code nearby to
read the KHG anyway, and I want to shift the emphasis from
officially documenting the Linux kernel to being a learning
resource about the Linux kernel--one that may well be useful to
other people who want to document one part or another of the
Linux kernel more fully, as well as to people who just want to
hack the kernel.